title: [Two cases of retroperitoneal tumors].
mesh_terms: D005354:Fibrosarcoma; D007680:Kidney Neoplasms; D009369:Neoplasms; D010534:Peritoneal Neoplasms; D010537:Peritoneum; D012186:Retroperitoneal Neoplasms
keywords: FIBROSARCOMA; KIDNEYS/neoplasms; PERITONEUM/neoplasms
vernacular_title: A proposito de dos casos de tumores retroperitoneales.